Posted by MoparNorm on Wednesday, January 03, 2007 at 13:13:02 :
In Reply to: Exhaust Valve Seats Revisited posted by Vaughn on Wednesday, January 03, 2007 at 12:29:21 :
Thanks Vaughn, just to clarify "lead additives" no longer exist, lead is banned and is illegal to use in motor vehicles and many other applications in the United States, what is available is "lead substitutes" to add lubrication/cooling properties to the fuel, but in my opinion they are a waste of money.
A non-hardened exhaust valve seat will likely last for about 35,000-50,000 miles as is. During that time, the user can take the money saved by not buying the additive, but the money in the bank and buy the inserts at the next re-build.
Some Mopar motors had "valve rotators" that will add life to the valves and keep them cooler.
When I rebuilt my Poly I did not install inserts, there is little room in the Poly head for inserts and they would ruin the perfect shape of the combustion chamber... and I just couldn't bring myself to mutilate that head. If they don't last, then I will re-consider inserts at that time. In a flat head there is less of a chance to harm performance with an insert, so they may make more sense in that application.
MN
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